A "Subprime borrower" Is somebody who has a poor credit history or some other indication that would suggest that they might not be able to repay the mortgage-- they might default.

次级借款人"指的是,那些信用记录较差的借款人,或在其他方面显示,他们很可能无力偿还贷款,也就是说他们很可能违约

耶鲁公开课 - 金融市场课程节选

They are borrowers that are thought, by the various models, to be likely to fail to pay on their mortgage and to have to be foreclosed; often low income, but also they're people with poor credit histories.

通过一些模型的计算,这些借款人,很有可能无法偿付贷款,抵押房产会被贷款人收回,借款人通常属于低收入人群,而且这些人没有很好的信用记录

耶鲁公开课 - 金融市场课程节选